Terms of Use

Effective date: August 29, 2026 · Last updated: August 29, 2026

These Terms of Use (“Terms”) govern your use of the THEO mobile application, website, and related services.

THEO is operated by Dmitrii Tsariabin, an independent individual developer (“THEO,” “we,” “us,” or “our”). By accessing or using THEO, you agree to these Terms.

1. The THEO service

THEO is an AI-powered English speaking practice service. It may provide live voice conversations, conversational prompts, corrections, summaries, vocabulary suggestions, speaking statistics, level adaptation, reminders, and other learning-related features.

2. Language-practice tool, not a guaranteed course

THEO is designed to help you practice English through conversation. It does not guarantee a particular language level, exam result, certification, learning speed, accent, fluency outcome, employment outcome, or academic result. Your progress depends on many factors, including frequency of use, prior knowledge, and how you practice.

3. AI-generated conversations

Some or all THEO responses are generated or assisted by artificial intelligence. AI systems can misunderstand speech, make grammatical or factual mistakes, provide imperfect corrections, repeat themselves, or generate unexpected or inappropriate content. You are responsible for evaluating THEO’s output before relying on it.

4. No professional or emergency advice

THEO is a language-practice product, not a professional adviser or emergency service. Do not rely on THEO for medical, legal, financial, safety-critical, emergency, immigration, mental-health, or other professional decisions. If a conversation touches those subjects, any response is provided only as conversational language practice.

5. Eligibility

You may use THEO only if doing so is lawful where you are located. If you are below the age required to enter into an enforceable agreement or independently consent to online services in your jurisdiction, you may use THEO only with permission or involvement from a parent or legal guardian where required.

6. Your voice and conversation content

You retain any rights you may have in the words, voice content, or other material you submit to THEO.

By using voice or text features, you grant THEO a non-exclusive, worldwide, royalty-free license to receive, host, transmit, reproduce, process, analyze, transform, and generate derived information from that content only as reasonably necessary to provide the requested conversation, maintain learning progress and personalization, secure and troubleshoot the service, and operate THEO.

This license does not transfer ownership of your content to THEO.

7. Sensitive information

THEO is built for English conversation practice, not for storing secrets or sensitive records. Do not intentionally provide passwords, authentication codes, payment-card details, government identification numbers, confidential business secrets, private third-party communications, or other information that you do not want processed by an online AI service.

8. Acceptable use

You may not use THEO for unlawful purposes; interfere with or disrupt the service; bypass limits, security measures, or subscriptions; access THEO through unauthorized automated systems; scrape or systematically extract data; probe systems for vulnerabilities without authorization; reverse engineer components except where applicable law expressly permits it; impersonate another person; distribute malware; use the service to facilitate illegal activity; or abuse promotional, free-use, or subscription limits.

9. Subscriptions and paid features

THEO may offer subscriptions, trials, or other paid functionality. If you purchase through the Apple App Store, payment is processed by Apple and billing is subject to Apple’s terms. Unless otherwise stated by Apple or required by law, subscriptions may automatically renew unless cancelled before renewal through your Apple account settings. Refund eligibility is generally governed by Apple’s policies and applicable law.

Deleting THEO from your device does not automatically cancel an active subscription.

10. Notifications

If you enable notifications, THEO may send reminders, practice prompts, subscription-related information, or other service messages. You can disable app notifications at any time through iOS Settings.

11. Third-party services

THEO relies on or integrates with third-party services, which may include cloud infrastructure, artificial-intelligence and speech providers, analytics and diagnostics systems, notification services, subscription-management systems, and Apple platform services. THEO is not responsible for third-party products, policies, outages, or representations.

12. Availability of THEO

We aim to keep THEO available, but we do not guarantee uninterrupted or error-free operation. The service may be unavailable or degraded because of maintenance, software errors, AI-provider issues, third-party outages, network problems, excessive demand, security incidents, device limitations, or circumstances beyond our reasonable control.

13. Changes to the service

THEO is an evolving product. We may add, modify, remove, limit, redesign, or discontinue features at any time, including conversation models, voices, usage limits, free features, subscriptions, learning metrics, and notifications.

14. Intellectual property

Except for content owned by users or third parties, THEO and its software, design, branding, interfaces, text, graphics, systems, models of interaction, and related intellectual property are owned by or licensed to the operator of THEO. These Terms do not transfer ownership of THEO intellectual property to you.

15. Feedback

If you voluntarily provide suggestions, ideas, comments, or other feedback concerning THEO, you grant us the right to use that feedback without restriction or compensation to you.

16. Privacy

Our processing of information is described in the THEO Privacy Policy available at go-theo.com/privacy.

17. Disclaimer of warranties

To the maximum extent permitted by applicable law, THEO is provided on an “as is” and “as available” basis. We disclaim warranties not expressly required by law, including implied warranties of merchantability, fitness for a particular purpose, accuracy, learning outcomes, availability, and non-infringement.

18. Limitation of liability

To the maximum extent permitted by applicable law, THEO and its operator will not be liable for indirect, incidental, special, consequential, exemplary, or punitive damages arising from or relating to your use of the service, including losses arising from inaccurate speech recognition, incorrect language corrections, inaccurate AI responses, service interruptions, loss of learning history, missed notifications, or reliance on AI-generated content.

19. Suspension and termination

You may stop using THEO at any time. We may suspend or restrict access where reasonably necessary because of violation of these Terms, suspected fraud or abuse, security risk, legal requirements, misuse of infrastructure, non-payment where applicable, or conduct that materially harms THEO, its systems, or other users.

20. Changes to these Terms

We may update these Terms from time to time. If we make material changes, we may provide notice through the application, website, or another reasonable method when required. The “Last updated” date indicates the latest revision.

21. Contact